Hard lead alloy



, UNITED STATES PATENT OFFICE.

GEORGE H. WOBBAIIIJ, OF KIRKWOOD MISSOURI, ASSIGNOR '10 UNITED LEAD COM- PANY, 01?.NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

mum LEAD ALLOY.

Specification-of Letters Patent. P t t No 30, 1920.

Ho Drawing. Application filed August 25. 1919, Serial No. 319,669. Renewed Kay 28, 1920. 'Serial To all whom-it may concern Be it known thatI; Gnome H. WORRALL, United States citizen, residing in Kirkwood, Missouri, have invented the following-described Improvements in Hard Lead Alloys.

I have discovered that, in small amounts,

mercury has the property of increasing the amounts of sodium. potassium, magnesium or'lithium or combinations of these leadhardening metals. with or without other additions. By way of example of the effect of mercury on these and other alloys it may be stated that the addition of mercury to an alloy containing lead 99.5% and calcium increases the hardness equivalent to that of lead containing nearly twice the amountof calcium, other conditions being constant. Calcium is one of those lead-hardening metals most conveniently combined with lead by electrolytic deposition from its fused salt, and it is therefore apparent that the addition of mercury reduces the time of electrolysis, and hence the cost of production of; the alloy. by approximately half, while the cost of the mercury itself is trifling by comparison. The mercury also improves the resulting alloy for bearing metal and general casting purposes by rendering it more fluid in its fused state.

The same advantages obtain in varying degrees with other lead-base alloys and I have ascertained that even lead alone is also somewhat hardened by a small addition of mercury. The amount of mercury necessary for the'purposes of the invention is variable according to the degree of hardness desired and the character oi the metal or metals used with or present in the lead as the main hardening-agent and no definite percentage can therefore be )rescribed for all materials and conditions. he range lies far below the percentages producing the socalled amalgams, which are not suitable for bearmg-metal purposes and in actual practice is confined between the limits 1% and of the whole alloy but with some alloys, one per cent. and even higher percentages produce the characteristic improvements above described. The maximum limit for each composition is the point where the mercury ceases to harden the alloy and in general the practical upper limit of usefulness 15 around 3% according to my present belief. Additional ingredients may beintroduced into or used with the mercury-hardened alloys of this invention for various purposes such as resisting the tendency to dross or controlling the appearance, weight or otherwise. It has been ascertained that aluminum, in very small amounts, tends to prevent the dressing of lead-base alloys and on this account I prefer to use aluminum in my alloys when necessary. When so used it is introduced in amounts approximately .02% of the whole alloy and inasmuch as aluminum does not readily mix with lead it is generally introduced alloyed with a small amount of tin, zinc, or magnesium acting as a carrier, or a mixture of oneformore of these metals in. small amounts aggregating, for non-drossing purposes, approximately of the total alloy.

The process of manufacture according to this invention comprises first combining the lead with the principal hardening metal, as for example, any of the metals above indi cated, namely, calcium, strontium, magneslum, sodium, potassium or' lithium, with or without barium. and then while molten or remelted adding the requisite small amount the hardening metal or metals has been absorbed by the lead whereupon the molten alloy is removed to another vessel and when somewhat cooled the mercury is added in amount suflicient to raise the hart-bless to the point previously determined upon. The non-dressing agent and such other ingredicuts as are desired may also be added at the same time and preferably previously to the addition of the mercury. I prefer at present to use my invention according to the following formula which includes two of the alkaline earth metals as the main hardening agent Barium between .90 and 1.10%, calcium between .40 and .60%, mercury between .10 and 25%, to which is added to the extent of about 35%, a mixture of the zinc or magnesium with aluminum and sufficient to carry about 02% of aluminum into the alloy. The balance of the alloy is lead. The barium and calcium are first alloyed with the lead electrolytically as above described,

the alloying process being continued for such period as will produce substantially the indicated proportions of these metals and a hardness less than desired in the product alloy. VVhereupon, in another vessel, an amount of mercury suflicient to bring the hardness up to the desired point is added together with the non-drossing ingredient. In this manner a predetermined degree of hardness may be obtained with accuracy. The proportions above stated produce adegree of hardness approximating 25 or better on-the Brinell scale. The alloy is tough and excellently adapted for all bearing metal purposes and for general die-casting. Certain specific combinations of the metals herein mentioned but not specifically claimed form the subjects of collateral applications.

Claims:

1. The method of making lead alloys of predetermined hardness which consists in hardening a lead base alloy containing upward of 90% lead by adding thereto a small percentage of mercury.

2. The method of making hard lead alloys of predetermined hardness which consists in compounding lead with a lead hardening metal or metals in amounts adapted to produce a certain degree of hardness and increasing such hardness to a predetermined point by introducing a small percentage of mercury in the composition.

3. The method of making lead base alloys which consists in electrolytically alloying therewith a lead-hardening agent and thereafter increasing the hardness of such alloy by adding thereto a small percentage of mercury.

4. A hard lead alloy suitable for bearings and like uses containing upward of 90% lead, a lead hardening metal and a small percentage of mercury coacting therewith to increase the hardness of the alloy.

5. A metallic composition suitable for bearings and like purposes comprising an alloy containing lead 90% or upward. a lead-hardening metal and a small percentage of mercury coacting with said metals to increase the hardness thereof.

6. A hard lead alloy containing lead and one or more metals of the alkaline earth metals and having its hardness increased by the presence therein of a small percentage of mercury.

7. An alloy comprising upward of 90%v lead, calcium and a small percentage of mercury.

8. An alloy comprising upward of 90% lead, two or more lead-hardening metals and a small percenta e of mercury.

9. A hard lead aloy comprising lead, calcium. barium and a small percentage of mercury.

10. A hard lead alloy containing between .9% and 1.10% barium. between A)? and .6% calcium and between .107v and .2571 mercury.

In testimony whereof I have signed this specification.

GEORGE H. \VORRALL. 

